1. Field of the Invention
The present invention relates to a position determining apparatus that reciprocally moves or rotates a laser source emitting laser beam to produce an inclined plane meeting a horizontal reference plane at a certain inclination angle, and a rotary laser apparatus used with the same. The position determining apparatus according to the present invention is useful to produce a reference point, a reference line, and a measurement reference plane.
2. Prior Art
In order to produce a horizontal reference level that covers a wide range, a rotary laser apparatus has been increasingly replaced with an optical leveling apparatus.
For recent years, the rotary laser apparatus has been used to determine an elevation in relation with some directions, especially, to produce line, plane, and so forth based upon a reference elevation. The rotary laser apparatus emits horizontal laser beam while having the laser beam circularly or reciprocally sweep and then interrupt, so as to produce a rotation reference plane, a partial reference line, a reference plane, a reference line, a reference point, or the like.
The rotary laser apparatus is suitable for applications where it is used to produce a reference horizontal line based on which an area is designated in reserve for a window frame of a building under construction and where it is used to build a mount and produce a reference horizontal plane based on which the mount is cut and sectioned to create exposed faces of soil. In another application, the rotary laser apparatus is used to predetermine reference points to build inclined structures such as stairs, and in some other application, the rotary laser apparatus can produce reference plane inclined in one direction or even in two directions.
An example of the prior art rotary laser apparatus, which is capable of creating inclined reference plane, is disclosed in Japanese Patent Laid-Open No. H06-26861. Configuration and features of the prior art rotary laser apparatus will be outlined below.
Referring to FIG. 44, a rotary laser apparatus 951 has a casing 901 and a laser projector 903. The casing 901 has its upper center portion provided with a recessed portion 902 shaped in a frustum of a cone. The laser projector 903 vertically extends through the center of the recessed portion 902. The laser projector 903 supported by the recessed portion 902 can be tilted on and around a spherical mount 904 formed in the middle thereof. A rotary unit 905 provided with a pentaprism 909 is mounted in an upper portion of the laser projector 903. The rotary unit 905 is rotated through a drive gear 907 and a sweep gear 908 powered by a sweep motor 906.
Two units of inclination mechanism (only one of them is illustrated) are attached around the laser projector 903. Either of the units 910 of the inclination mechanism includes a motor 911, a screw 912, and a nut 913 that are all cooperatively work to make inclination. The motor 911 is capable of turning the screw 912 through a drive gear 914 and a tilting gear 915. The laser light projector 903 is coupled to the nut 913 with the arm 916 intervening between them. Turns of the screw 912 cause the nut 913 to move up and down, which brings about inclination of the laser light projector 903.
Two fixed sensors 918 and 919 are positioned in the middle of the laser light projector 903 in the same plane orthogonal to a rotation axis of the rotary unit 905. One of the fixed sensors, the sensor 918, is positioned in parallel with the tilting arm 916 while the other, the sensor 919, is oriented orthogonal to the tilting arm 916. A flange 920 having a pivot pin 921 is fixed to a lower end of the laser projector 903. An upper end of the pivot pin 921 pivotally supports an L-shaped tilting plate 922 at one point thereon, and an angle-determining sensor 929 and an angle-determining sensor 930 are incorporated in the L-shaped tilting plate 922. The angle-determining sensor 929 is positioned in the same direction as the fixed sensor 918 while the angle-determining sensor 930 is positioned in the same direction as the fixed sensor 919. The tilting plate 922 is connected to a couple of units of inclining mechanism (only one unit is shown).
Each of the units 925 of inclining mechanism includes a motor 926, a screw 927 rotated by the motor 926, and a nut block 928 through which the tilting screw 927 is screwed down, all of these components being cooperative to make the reference to inclination. One end of the tilting plate 922 is fitted on the nut block 928. The motor 926 is actuated to rotate the screw 927 and vertically move the nut block 928, and thus, the tilting plate 922 can be inclined.
A laser illuminator (not shown) and a projector optical system (not shown) including optics such as a collimator lens that refracts incident rays from the laser illuminator into parallel rays are built in the laser projector 903. Laser beam emitted from the projector optical system is deflected in horizontal direction by the pentaprism 909 and projected out of a projector window 931.
Functional features of the rotary laser apparatus will now be described. Determination of an inclination angle is carried out by the inclining mechanism 925. First, the inclination mechanism 910 is actuated to regulate postures of the fixed sensors 918 and 919 so that both of the sensors indicate they are horizontal. The motor 926 is then actuated to rotate the screw 927 and lift the nut block 928, and consequently, the tilting plate 922 is inclined at an angle θ relative to the flange 920 in a reverse angular direction to the desired predetermined angle θ. The inclination angle θ is detected by a component such as an encoder (not shown) linked to the motor 926.
Then, the inclination mechanism 910 is actuated to tilt the laser projector 903 so that the tilting plate 922 is detected as being horizontal. At this posture, an emission direction of light from the laser projector 903 inclines at the predetermined angle θ relative to the horizontal plane. After the inclination angle in the emission direction of the laser light is determined, the laser beam deflected at the pentaprism 909 in a direction orthogonal to the rotation axis of the rotary unit 905 is projected through the laser projector 903 while the rotary unit 905 is being rotated or the rotary unit 905 is reciprocally sweeping within a range equivalent to the predetermined angle, so as to create an inclined reference plane.
Japanese Patent Laid-Open No. H11-94544 discloses a post-construction elevation display apparatus and a post-construction elevation determining apparatus both of which are comprised of a laser device rotating simultaneous with irradiating laser beam and a finished elevation display. The post-construction elevation determining apparatus can determine a desired post-construction elevation by using the post-construction elevation display to receive laser beam irradiated by the laser device so as to detect a distance from the laser device to the display device and a deviation between the display device and a reference horizontal plane against which the laser beam is directed.
Furthermore, Japanese Patent Laid-Open No. H11-118487 discloses a reference irradiated beam detecting apparatus incorporated with an inclination angle sensor, which is used in combination with a laser apparatus.
Additionally, Japanese Patent Laid-Open No. H7-208990 discloses a 3-dimensional coordinate determining apparatus including an irradiating means rotating and irradiating a plurality of plane beams and more than one reflecting means. The 3D coordinate determining means uses the plurality of reflecting means to reflect light emitted from the irradiating means and uses the irradiated means to receive the reflected beams to determine 3-dimensional coordinates in relation with the reflecting means.
The prior art rotary laser device as in the above statement must have two pairs of units of inclining mechanism which support the laser projector 903 in a manner where the laser projector can have a full freedom of tilting in two ways, in order to produce inclined reference planes. Such a prior art embodiment is disadvantageous in that it needs two of the fixed sensors 918 and 919 and two of the tilting sensors 929 and 930 and in that it requires a complicated configuration, i.e., it needs a control circuit to control an actuation of two of the pairs of the units of inclining mechanism, which results in an increased manufacturing cost. Moreover, the prior art rotary laser device disadvantageously produces only one reference plane but can never produce horizontal and inclined reference planes simultaneously, which disturbs determining a relative relation between the horizontal and inclined reference planes, or which disturbs determining a relative relation between two inclined reference planes different in inclination angle from each other.
The prior art embodiment of the 3-dimensional coordinate determining device as disclosed in Japanese Patent Laid-Open No. H7-208990 should be further improved by accurately regulating an angular position of the reflecting means so as to return beams reflected from the reflecting means to the irradiating means assuredly. Additionally, the reflecting means must be moved in producing the predetermined reference plane, and a determination value also must be monitored at the irradiation means, which disadvantageously results in requesting more than one operators to dedicate themselves in handling the device.
In order to overcome the aforementioned disadvantage, the present invention provides an improvement of a rotary laser apparatus that permits a simultaneous determination of an inclined plane and a horizontal reference plane at any elevation without tilting a laser projector and without precisely positioning a light receiving section.
Accordingly, it is an object of the present invention to provide a position determining apparatus of a simplified mechanism that is capable of producing a horizontal reference plane and an inclined plane simultaneously.
It is another object of the present invention to provide a position determining system of simplified manipulation which permits a single operator to work sufficiently.
It is still another object of the present invention to provide a rotary laser apparatus that is capable of emitting a fans-shaped laser beam diverging in a plane other than horizontal plane.
In an aspect of the present invention, a position determining apparatus is comprised of a rotary laser apparatus that emits two or more fan-shaped laser beams while rotating the laser beams about a given axis, and an optical sensor that has one or more light receiving sections receiving the fan-shaped laser beams, where the two or more fan-shaped laser beams diverge in a plane other than horizontal plane. At least one of the fan-shaped laser beams is different in inclination angle from the remaining beams, and the optical sensor determines a relative position of itself to the rotary laser apparatus, relying upon a state of the fan-shaped laser beams received at the light receiving section. At least two of the fan-shaped laser beams preferably intersect each other in the horizontal plane. Preferably, the optical sensor determines the relative position of itself to the rotary laser apparatus, depending upon a delay of time between detections of two of the fan-shaped laser beams at the light receiving section, and also preferably, the optical sensor includes two ore more light receiving sections that receives the fan-shaped laser beams.
In another aspect of the present invention, the position determining apparatus has a rotary laser apparatus that emits two of the fan-shaped laser beams different in polarization from each other. Preferably, two of the fan-shaped laser beams are modulated into different frequencies from each other, and also preferably, two of the fan-shaped laser beams are of different wavelengths from each other. With the rotary laser apparatus configured in this fashion, two of the fan-shaped laser beams can be distinguished from each other, and a measurement can be attained with accuracy in the event of short delay of time between detections of the laser beams.
In still another aspect of the present invention, the rotary laser apparatus in the position determining apparatus includes a detector means for detecting emission directions of the fan-shaped laser beams and a transmitter for transferring angular data detected by the detector means to the optical sensor, and alternatively, the optical sensor may include a receiver unit that receives signals of the angular data.
Moreover, in the position determining apparatus according to the present invention, the optical sensor may have a position sensor that detects a relative position of the rotary laser apparatus to the optical sensor. Preferably, the position sensor is a GPS. With the position determining apparatus configured in this manner, the relative position of the optical sensor to the rotary laser apparatus in the horizontal plane can be determined.
Furthermore, each of the fan-shaped laser beams may be varied in intensity from one part to another. Preferably, the rotary laser apparatus emits three or more of the fan-shaped laser beams which intersect the horizontal plane equidistant from one another. With the position determining apparatus configured in this way, influence on a measurement due to a rotation error of the rotary laser apparatus can be minimized.
It is preferable that three or more of the fan-shaped laser beams do not intersect one another within a range where they are to be optically sensed. In this manner, the fan-shaped laser beams are sensed at a certain delay of time from one another, and hence, interference among the fan-shaped beams can be avoided. Thus, a measurement can be attained with accuracy without polarizing the laser beams differently or without modulating them into different frequencies from one another.